Disc computer for use in pipe bending



Aug. 10, 1965 G. H. MARTENS DISC COMPUTER FOR USE IN PIPE BENDING- z Sheets-Sheet 1 Filed Dec. 20, 1963 INVENTOR.

GEORGE H. MARTENS ATTORNEY Aug. 10, 1965 G. H. MARTENS DISC COMPUTER FOR USE IN PIPE BENDING 2 Sheets-Sheet 2- Filed Dec. 20, 1963 INVENTOR.

GEORGE H. MARTENS ATTORNEY United States Patent kit My invention relates to a disc computer which is used to calculate the data necessary for the proper bending of pipe, particularly the pipe used in the construction of cross country pipe lines.

The individual lengths of pipe which are welded together end to end to form a pipe line are called joints. They are usually fabricated from steel. Gne of the major tasks in the construction of a cross country pipe line is the bending of these joints to conform them to the contour of the land across which the pipe is being laid.

Pipe line workers use descriptive terms to describe the three basic kinds of bends that are given to the joints. A sag is an upward bend that is given a joint when the pipe line is crossing a gulley or other concave depression in the land. An overbend is a downward bend given a joint when the pipe line is traversing a hill or other conex feature of the land. A sidebend is a bend in a joint either to the right or the left. it is formed in a pipe whenever the pipe line must veer around some obstruction in its path or change direction.

Various combinations of a sag, an overbend and a sidebend are often required. Both the combination of a sag and an overbend and the combination of a sidebend left and a sidebend right are called reverse bends. Any bend which consists of both a sidebend and either a sag or an overbend is called a combination bend. The four possible combination bends are commonly referred to as a sag left, a sag right, an overbend left and an overbend right. The bend resulting when a single joint of pipe is given two or more bends having ditferent planes is called a corkscrew bend.

Several different techniques may be employed to bend a pipe joint. Joints with larger diameters, eighteen inches and greater, are generally bent on specially constructed bending machines operated either hydraulically or with cables.

Two general types or classes of bending machines are in widespread use today. A horizontal bending machine bends the joint in a horizontal plane. A vertical bending machine bends the pipe in a vertical plane. Normally, a vertical bending machine always bends upward so that a bent joint of pipe in the machine will always by in a sag or concave position. For purposes of simplicity and convenience, my invention will be described for use with such a vertical bending machine. it is, of course, easily adapted for use with a horizontal bending machine, as the principles of the invention apply to both types of machines.

Joints with smaller diameters are frequently bent with a bending shoe mounted on the side of a boom tractor. Whatever the technique used, the data describing a particular bend must be accurately calculated in order that the bend may be properly made.

The data describing the bend itself includes four important angles that are illustrated in FIG. 4, which is a perspective view of a bent joint. The bent joint til shown in FIG. 4 has a straight portion 1?. and an oblique portion 1.2. A first important angle is the angle between the extension of the straight portion lit and the oblique portion 1.2.. It is called the total angle T. A second important angle is the horizontal angle 1*. It is the angle between the oblique portion 12 and the projection of the oblique portion 212 on the vertical plane determined by the straight portion it. The counterpart of the horizontal angle H is the vertical angle V, which is a third important angle.

Patented Aug. i9, 1%65 This vertical angle V is the angle between the oblique portion 322 and the projection of the oblique portion 12 on the horizontal plane determined by the straight portion ll. A fourth important angle is the twist angle R. it is the angle between the vertical plane determined by the straight portion ill. and the plane determined by the oblique portion l2. and its projection on a vertical plane which is perpendicular to the straight portion ill.

These four angles are determined by the contour of the land over which the pipe line is crossing. Usually the horizontal angle H and the vertical angle V are known from direct measurement of the contour.

The total angle T is computed from the measured values of the horizontal angle H and the vertical angle V. It is the important angle required to be known for operation of a bending machine. A joint is bent in the bending machine by an amount equal to the magnitude of the total angle T. The twist angle R, which is calculated from the total angle T and the horizontal angle H, is the important measuring angle when the bent joint is being laid in place in the pipe line. For any sidebend or combination bend, the bent joint must be rotated or twisted from the plane of the bend while being laid in the pipe line, to turn the oblique portion 12 or" the bent joint 10 in the direction of the sidebend. The twist angle R measures the amount of twisting or rotation that is required. The bent joint is not twisted in the sense that it is physically deformed. It is merely turned to point it in the direction of the sidebend. Any combination bend thus involves both a bending of the joint in the bending machine and a twisting of the joint to position it properly in the pipe line.

The topmost or top center point of a joint positioned in a pipe line is called the lay pipe mark. The lay pipe mark of a joint is usually placed on the circumference of the joint adjacent the near end of the joint as viewed in the direction the pipe line is progressing, and is chosen arbitrarily or as dictated by contract specifications. The description assumes the lay pipe mark is placed on the near end. The joint must be properly positioned in the bending machine to insure that the chosen lay pipe mark will be the uppermost point on the near end of of the joint when the joint is laid in the pipe line.

The topmost or top center point of a joint positioned for bending in a bending machine may be referred to as the bend mark. The bend mark is located on the same end of the joint as the lay pipe mark. The lay pipe mark is the orientation mark for both determining the location of the bend mark on the joint, and for the welding of the joint in the pipe line. When it is desired to form a combination sag bend in a joint with a vertical bending machine of the type described above, the bend mark is displaced from the lay pipe mark an arcuate distance along the circumference of the joint subtended by the angle of twist R. When it is desired to form a combination overbend in a joint, the bend mark is displaced from the lay pipe mark an arcuate distance along the circumference of the joint subtended by an angle equal to less the angle of twist R. The direction in which the distance is measured around the joint depends upon the horizontal direction of the combination bend. Thus, the bend mark for the combination bends sag left and overbend left is measured counterclockwise from the lay pipe mark, whereas the bend mark for the combination bend sag right and overbend right is measured clockwise from the lay pipe mark.

When laying and welding the pipe line, the welding crew need only determine that the lay pipe mark on each joint is the uppermost point on the pipe. As soon as the lay pipe mark is so positioned, the near end of 89 the joint can be welded to the adjacent joint in the pipe line.

Two main problems arise in pipe bending. One is the calculation of the total angle T and the twist angle R from the horizontal angle H and the vertical angle V. The second is the orientation of the joint in the bending machine (determination of the position or" the bend mark with respect to the lay pipe mark). The second problem is expecially apparent in the formation of corkscrew bends. A joint having two combination bends requires a separate bend mark for each bend. Thus, it is necessary to twist the joint in the bending machine to a new position with respect to the lay pipe mark for each bend.

If the proper relative position of the bends is obtained, the welding crew simply twists or rotates the joint to place the lay pipe mark in its uppermost position and the joint is properly positioned for welding in the pipe line. Calculation of the amount of twisting of the joint in the bending machine during the interval between the formation of the first and second combination bonds is accordingly vital.

Twisting a joint in a bending machine is also vital in another common situation. Most joints are fabricated from a single section of steel which has two opposing edges welded together in a longitudinal seam. Contract specifications for pipe lines often demand that the longitudinal seam be located in a specific position with respect to the lay pipe mark or with respect to the longitudinal seams in the succeeding and preceding joints. When a combination or corkscrew bend is being made, therefore, the lay pipe mark must be correctly chosen in relation to the seam, and the joint must be properly located in the bending machine with respect to its lay pipe mark. If it is not, the seam will not be properly located, except by chance, when the bent joint is twisted to properly locate it in the pipe line.

Prior to my invention the calculation required to determine the amount to twist a joint with respect to its lay pipe mark in a bending machine was performed with pencil and paper. The calculation was tedious; errors were likely. My invention ends the need for such a manual calculation.

It is a primary object of my invention to provide a device which may be used to quickly calculate the data required to properly bend a pipe.

It is a further object of my invention to provide a device which can be used to accurately determine the amount which a bent joint must be twisted to properly position it in a pipe line.

Another object of my invention is to provide such a device that pictorially indicates the amount and direction of the twisting.

A further object of my invention is to provide such a device that is inexpensive and easily usable by persons not having mathematical training.

Other objects and advantages of my invention will be apparent from the following detailed description taken in conjunction with the accompanying drawings wherein a preferred embodiment of the principles of the invention has been selected for exemplification.

In the drawings:

FIG. 1 is a plan view of one face of my novel disc computer.

FIG. 2 computer.

FIG. 3 is a section view taken along line 3-4 in FIG. 1.

FIG. 4 is a perspective view of a bent joint.

My inventive disc computer 13 preferably comprises the three discs l4, l and 16 concentrically mounted one on top of the other, as shown in FIG. 3. The middle disc has the largest diameter and carries scales on both of its faces. The outer discs 14 and lo preferably are approximately the same size and carry scales on their is a plan view of the other face of my disc sin T=sin H sin V and sin H Sm sin T As previously stated, the horizontal angle H and the vertical angle V are known or can be determined by direct measurement. Using their known values, the value of the total angle T is calculated. Once the total angle T is known, it and the horizontal angle H are used to compute the twist angle R. The scales carried by the front face 18 of the disc 15 and the outer face 19 of the disc l4 permit these two calculations to be performed mechanically.

The corresponding arcuate scales 20 and 21 carried respectively by the front face 18 of the disc 15 and the outer face 1% of the disc 1d perform the addition indicated by the formula sin T=sin V-j-sin H The scales 2%) and Zll are identical in their graduations, but are opposed. Because they are opposed, the addition performed by the scales is direct. Thus, if the mark for the vertical angle V on the scale id is matched to the mark for the horizontal angle H on the scale 21, the 0 mark on either scale points to the total angle T on the other scale. The 0 marks on the two scales 2% and 21 are therefore shown as arrows labeled Total Angle, as illustrated in FIG. 1. It is immaterial whether the horizontal angle H is taken on the scale 20 and the ertical angle V on the scale 21, or vice versa. The same answer for the total angle T obviously results in either case.

One way of graduating the scales 2% and 21 is to make the arcuate distance on the scales from the zero mark to the mark for the angle to be represented proportional to the square of the sine of that angle. For example, suppose the mark is for 30. The square of the sign of 30 is 0.250. The mark for 30 may arbitrarily then be placed an arcuate distance of from the zero mark. The square of the sine of 10 is 0.031. The mark for 10 would then be placed 0.03l/0.250 125 or 15.5 from the Zero mark.

The range of from 0 to 30 for the scales 20 and 21 shown in FIG. 1 is exemplary only. A range covering any number of degrees may be used. Because of the nature of the sine squared functions, the scales 20 and 21 are contracted in the range from 0 to 10. For greater accuracy in this low range, therefore, a second pair of scales similar to the scales 2t} and 251, but with the range from 0 to 10 expanded, may be added to my disc computer 13 if desired.

The matching, arcuate scales 22 and 23 carried respectively by the front face 18 of the disc l5 and the outer face 19 of the disc 14 perform the division indicated by the formula sin H sin R= sin T The disc computer 114 performs such division by the logarithmic subtraction log sin R-log sin H-log sin T tional to the logarithm of the sine of the angle which designates that graduation.

To obtain the twist angle R, the horizontal angle H is found on the scale 22 and matched to the total angle T as found on the scale 23. The 90 mark on the scale 23, which is an arrow designated Angle of Twist in FIG. 1, then points to the twist angle R on the scale 22.

@nce the twist angle R is known, the disc computer is turned over to expose for use the scales on its other side. These scales, four in number, perform the vital function of pictorially indicating how a joint should be positioned in a vertical bending machine of the type previously described to properly orient the joints lay pipe mark.

The periphery of the rear face 24 of the disc carries a linear scale 25 calibrated in inches. The outer face 26 of the disc 16 carries two corresponding, opposed arcuate scales 27 and 28, each with a range of 90 and covering an actual 90 arc on the disc 16. Also carried by the outer face 26 is a scale 29 consisting of the four arrows 3t) spaced at 90 intervals around a circle on the face 26. Two of the arrows 30 are the end points of the scales 27 and 28.

The zero mark on the scale 25 is labeled lay pipe. it corresponds to the lay pipe mark on a joint which is about to be bent in a bending machine. The scale 25 is calibrated in inches in either direction from the lay pipe mark. The complete distance around the circular scale 25 represents the circumference of the joint. For exemplary purposes only, the scale 25 shown in FIG. 2 is for a joint with a diameter of 36 inches. Such a joint has a circumference of approximately 113 inches. The distance from the lay pipe mark on the scale 25 to the point on the scale 25 diametrically opposite the lay pipe mark covers one-half of the circumference or approximately 56.5 inches. For use with joints of other diameters, other scales similar to the scale 25 and coaxial with it must be added to the rear face 24 of the 15. Another possibility is to provide for each joint of whatever size an associated computer 113 with a scale 25 corresponding to the diameter of that joint.

As labeled in FIG. 2, the opposed scales 27 and 23 of 90 actual degrees represent the angle of twist R. The terms SAG RIGHT, SAG LEFT, OB LEFT and OB RIGHT are shorthand respectively for bends of sag right, sag left, overbend left and overbend right. The scale 27, as shown in FIG. 2, is used for bends or sag left and overbend right. The scale 28 is used for bends of overbend left and sag right.

Each of the four arrows 39 corresponds to one of the four bends, sag left, sag right, overbend left and overbend right, as is shown in FIG. 2. The function of the arrows 39 is to pictorially indicate the position on the circumference of the joint of the bend mark with respect to the lay pipe mark, both in terms of distance and direction.

An example will illustrate the use of the scales 25, 27, 28 and 29. FIG. 2 is drawn to show the example. Suppose that the required bend is an overbend right and that the twist angle R, as determined from the scales 22 and 23, is 40. The scale 27 is used for overbend rights. The graduation for 40 on the scale 27 is matched to the lay pipe mark on the scale 2d. The arrow 30 marked OB RIGHT points to the graduation for approximately 44 inches on the scale 25. That graduation is located clockwise from the lay pipe mark on the scale 25. Hence, the bend mark is the point on the circumference of the joint which is 44 inches clockwise from the lay pipe mark on the joint. My new disc computer 13 thus pictorially indicates how a joint should be oriented when placed in a bending machine. It should be noted that my computer automatically accounts for the fact that the vertical bending machine forms sag bends only, so that no additional calculations are necessary to determine whether the joint must be rotated 180 when forming an overbend. The scales 25, 27, 2S and 29 give a true pictorial representation of the bend mark for any bend desired.

Because of the effective aid provided by my disc computer 13, the formation of a corkscrew bend is almost as simple as the formation of a single combination bend. Assume a corkscrew bend composed of two combination bends. The disc computer 13 is used to calculate the location of the bend mark for each combination bend, both as to distance and clockwise or counterclockwise direction, with respect to the lay pipe mark. The joint to be bent is then placed in the bending machine with the bend mark for the formation of the first combination bend properly oriented. After the first combination bend is formed, the joint is twisted in the bending machine an amount sufficient to properly orient the bend mark for the second combination bend, and the second combination bend is formed. Since each bend mark is independently deterrnined from the common lay pipe mark, the positioning of the joint for the second bend is no more difficult than for the first bend.

Similarly, no serious complication is added when contract specifications demand that the longitudinal seam for a joint be a certain distance from the lay pipe mark. Suppose, for example, that the seam is to be 15 inches clockwise from the lay pipe mark. The lay pipe mark is simply marked on the joint 15 inches counterclockwise from the seam. The bend mark for the joint is then found in the manner described in conjunction with the example shown by FIG. 2.

The marking of the scales 2'7, 28 and 29 for bends of sag right, sag left, overbend right and overbend left, as shown in FIG. 2, strictly applies only to a bending machine which receives the joint in a horizontal position, forms the bend in a vertical plane and always bends upward.

Because a sag bend is always formed in such a bending machine, the marks for two of the arrows 3d are quickly determined. Suppose a simple sag bend is required. The twist angle for a simple sag is zero. Since the bending machine assumed necessarily forms a sag, the bend mark for the joint is the same as the lay pipe mark for the joint. Consequently, as is shown in FIG. 2, the arrows 39 marked SAG LEFT and SAG RIGHT point to lay pipe mark on the scale 25 for a simple sag. They are the two arrows 36 which form the 0 marks for the scales 2'7 and 28.

Similarly, the marking of the scales 27, 28 and 29 for bends of sag right, sag left, overbend left and overbend right must be done with reference to one end or the other of the joint for the purpose of determining whether to mark the location of the bend mark for the joint as indicated by the arrows 3i; clockwise or counterclockwise from the lay pipe mark of the joint. Looking in the direction in which the pipe line is progressing, the marking shown in FIG. 2 refers to the near end of the joint.

Accordingly, it is expressly stated that the specific marking of the scales 2'7, 28 and 29 shown in FIG. 2 may be modified to relate to the far end of the joint without departing from the principles of my invention. Similarly, modifications of the position of the scales may be employed to adapt my invention for use with horizontal bending machines or downwardly bending vertical bending machines. In either case, the general principles described above are equally applicable.

It is further understood that my invention is not confined to the particular construction and arrangement of parts herein illustrated and described, but embraces all such modified forms thereof as come within the scope of the following claims.

I claim:

1. A disc computer comprising (a) a first, a second and a third disc,

(b) said first, second and third discs mounted one on top of the other in concentric, rotatable relation,

(0) said first and second discs carrying a first pair of '2? corresponding, opposed, arcuate scales graduated in degrees representing vertical and horizontal angles,

(d) said first pair of arcuate scales being graduated in proportion to the square of the sine of the angle marked on a graduation, said first pair of scales being adapted to cooperate to indicate a resultant total angle computed from said vertical and horizontal angles,

(c) said first and second discs further carrying a second pair of matching, arcuate scales graduated in degrees, one of the scales of said second pair of scales representing said total angle computed from said first pair of scales,

(f) said second pair of arcuate scales being graduated in proportion to the logarithm of the sine of the angle marked on a graduation, said second pair of scales being adapted to cooperate to indicate a resultant angle of twist,

(g) said third disc carrying a third pair of corresponding, opposed, arcuate scales representing said angle of twist and graduated in actual degrees and covering a range of 90,

(h) said third disc further carrying four marks spaced around a circle at 90 intervals,

(i) two of said four marks defining the end marks for said third pair of arcuate scales,

(j) said second disc further carrying an arcuate, linear scale covering a full circle, and

(k) said third pair of scales being adapted to cooperate with said lineal scale of said second disc to pictorially indicate the lineal amount and direction of twist corresponding to said angle of twist.

2. The disc computer of claim 1 wherein the first, second and third discs are substantially circular, said sec ond disc having a front face and a rear face and being mounted between said first and third discs, each of said first and third discs having an outer face, the first and second pairs of arcuate scales being carried on said front face of said second disc and said outer face of said first disc, the third pair of arcuate scales and the four arrows being carried on said outer face of said third disc, and the arcuate, linear scale being carried on said rear face of said second disc.

3. A disc computer for calculating the data required to properly bend a pipe joint, said computer comprising (a) a first, a second and a third disc,

(b) said first, second and third discs mounted one on top of the other in rotatable relation,

(c) said first and second discs each carrying one of the scales of a first pair of corresponding, opposed, arcuate scales with zero marks and graduated in degrees representing vertical and horizontal angles,

(d) the arcuate distance on each of said first pair of arcuate scales from said Zero mark to the graduation for a certain number of degrees being proportional to the angle whose sine is the square of the sine of that certain number of de rees, said first pair of scales being adapted to cooperate to indicate a resultant total angle computed from said vertical and horizontal angles,

(e) said first and second discs each further carrying one of the scales of a second pair of matching, arcuate scales with zero marks and graduated in degrees, the graduations on one of the scales of said second pair of scales representing said total angle computed from said first pair of scales,

(f) the arcuate distance of a graduation from said zero mark on each of said second pair of arcuate scales being proportional to the logarithm of the sine of the angle which designates the graduation, said second pair of scales being adapted to cooperate to indicate a resultant angle of twist,

(g) said second disc further carrying an arcuate, linear scale,

(h) said arcuate linear scale covering a complete circle,

(i) said third disc carrying a third pair of corresponding, opposed, arcuate scales graduated in actual degrees,

(j) each of said third pair of arcuate scales covering a range of (k) said third disc further carrying four marks spaced around a circle at 90 intervals,

(1) two of said four marks defining the end points for said third pair of arcuate scales.

4. The disc computer of claim 3 wherein the arcuate, linear scale has a reference mark, wherein the third pair of arcuate scales represents twist angles for joints of pipe, and wherein one of the four marks indicates a point on said arcuate, linear scale corresponding to the bend mark of a joint when said reference mark is aligned with the graduation for the twist angle for said joint on the appropriate scale of said third pair of arcuate scales.

No references cited.

LEO SMILOW, Primary Examiner.

UNITED STATES PATENT OEFICE CERTIFICATE OF CORRECTION Patent No. 3,199,777 August 10, 1965 George H Martens It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

In the drawings Sheet 2 Fig 2 scale 27, for the righ' end point designation "0" read 9O same Fig. 2, scale 28, for the right end point designation "90" read 0 in the heading to the printed specification, line 3, for "Praisa" read Prais column 1 line 48, for "by" read be column 4, line 72, for "R-log" read R=log columI 5, line 46, for "or" read of Signed and sealed this 19th day of April 1966.

(SEAL) Attest:

ERNEST W. SWIDER EDWARD J. BRENNER Attesting Officer Commissioner of Patents 

1. A DISC COMPUTER COMPRISING (A) A FIRST, A SECOND AND A THIRD DISC, (B) SAID FIRST, SECOND AND THIRD DISCS MOUNTED ONE ON TOP OF THE OTHER IN CONCENTRIC, ROTATABLE RELATION, (C) SAID FIRST AND SECOND DISCS CARRYING A FIRST PAIR OF CORRESPONDING, OPPOSED, ARCUATE SCALES GRADUATED IN DEGREES REPRESENTING VERTICAL AND HORIZONTAL ANGLES, (D) SAID FIRST PAIR OF ARCUATE ANGLES SCALES BEING GRADUATED IN PROPORTION TTO THE SQUARE OF THE SINE OF THE ANGLE MARKED ON A GRADUATION, SAID FIRST PAIR OF SCALES BEING ADAPTED TO COOPERATE TO INDICATE A RRESULTANT TOTAL ANGLE COMPUTED FROM SAID VERTICAL AND HORIZONTAL ANGLES, (E) SAID FIRST AND SECOND DISC FURTHER CARRYING A SECOND PAIR OF MATCHING, ARCUATE SCALES GRADUATED IN DEGREES, ONE OF THE SCALES OF SAID SECOND PAIR OF SCALES REPRESENTING SAID TOTAL ANGLE COMPUTED FROM SAID FIRST PAIR OF SCALES, (F) SAID SECONND PAIR OF ARCUATE SCALES BEING GRADUATED IN PROPORTION TO THE LOGARITHM OF THE SINE OF THE ANGLE MMARKED ON A GRADUATION, SAID SIECOND PAIR OF SCALES BEING ADAPTED TO COOERATE TO INDICATE A RESULLTANT ANGLE OF TWIST, 